Experiment on horizontal leaching characteristics of salt cavern gas storage

Abstract

The salt rock resource in China is characterized with multiple interlayers, thin salt formation and poor purity. Meanwhile, the conventional single vertical cavern has small volume and low utilization rate of salt formation, which cannot meet the requirements of rapid and efficient storage construction. Multi-step horizontal leaching can improve the utilization rate of salt formation and is suitable for constructing large gas storage in thin salt beds, and the cavern shape is a key factor affecting its volume and stability. Therefore, a physical simulation experiment was performed for the characteristics of horizontal leaching herein. Meanwhile, the effect of leaching parameters such as leaching rate, brine discharge position and back-step length on cavern shape and brine discharge concentration was explored. The results show that the large leaching rate and the high brine discharge position can reduce the brine concentration, and the effect is more significant in the early leaching stage. The small step length will form a hump cavern roof, while the large step length and use of blanket will form a flat cavern roof, and the alternate injection by two wells will form large body at both ends and small body in the middle. The cavern shape obtained by experiment is basically consistent with the numerical simulation result, which verifies the accuracy of experiment result. In addition, reference values were provided for such parameters as leaching rate and step length of multi-step horizontal leaching on site based on the experiment results, so as to build a hump-shaped horizontal cavern, further improving the stability and gas storage capacity of cavern.

Keywords

• salt cavern gas storage
• multi-step horizontal leaching
• solution-mining experiment
• leaching characteristic
• hump cavern roof